Civilization, goes an old maxim, is four meals away from barbarism – once the food deliveries stop, so does law and order. That could mean trouble for the political uprising in Egypt. It may also be what triggered it.

Scientists who study complex systems have been warning that ever-tighter coupling among the world's finance, energy and food systems would result in waves of political instability. Some say that is now happening in the Middle East.

Better models of the complex relationships in these systems could allow us to predict the next domino to fall.

For now, they show that there are two sides to complex interdependencies: they can generate cascading change, also known as revolution, but they can also collapse. At the minute, because so many aspects of Egypt's daily life are interlinked, the country is walking a fine line between the two.

As a result, the government maintains order with heavy subsidies for bread. It also runs the ports where imported wheat arrives, the trucks that haul it, the flour mills and bakeries. "Such hierarchical systems are both stable and unstable," says Yaneer Bar-Yam, head of the New England Complex Systems Institute in Cambridge, Massachusetts.

Headless hierarchy

By this he means that they are fine so long as the top of the hierarchy is in place, and can recover quickly. But take the top away – as is happening in Egypt – and the entire system risks collapse.

The early signs of this are showing. Bread is getting scarce in Egypt's capital, Cairo. Bakeries are closing for lack of flour and there have been reports that a baker who tried to raise prices was killed. Imported wheat is sitting in ports as cranes and lorries stand idle.

The interlocking dependencies that tie modern economies together spread dislocation further. Even where there is food, Egyptians have little money to buy it, as businesses and banks close, cash machines empty and wages dry up.

The situation is "a real concern", says Tad Homer-Dixon of the University of Waterloo in Ontario, Canada, who has warned previously that stresses including food shortages and poverty can cause catastrophic collapse in complex modern systems. It all depends on whether work resumes before the system hits the wall, says Homer-Dixon. In other words, if lorries and banks don't go back to work soon, widespread hunger could cause a breakdown of civil order.

The good news, says Bar-Yam, is that if you replace the top of the hierarchy, things start up again.

Food trigger

Egypt's uprising was triggered when Tunisia unexpectedly threw off a 30-year dictatorship last month. That uprising was triggered partly by food prices, which hit all-time highs in December.

Since then demonstrators in Algeria, Morocco, Jordan and Yemen have also protested about high food prices. Asian investment bank Nomura recently drew up a list of 25 governments most vulnerable to food shortages – in countries that depend on imports and whose people spend a third or more of their incomes on food – Egypt came sixth. Morocco, Algeria and Lebanon were in the top five; Tunisia came 18th.

The stresses of decades of dictatorship might have turned the entire Middle East into a "self-organised critical system" says Bar-Yam. The build-up of stresses makes such systems vulnerable to cascades of change triggered by relatively small disruptions. He and colleagues are trying to build mathematical models of the world's interlocking economic systems that might predict where the next instabilities will arise.

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